Methods for fabricating a semiconductor device and semiconductor devices fabricated by the same

ABSTRACT

The inventive concepts provide methods for fabricating a semiconductor device and semiconductor devices fabricated by the same. According to the method, conductive lines having a fine pitch smaller than the minimum pitch realized by an exposure process may be formed using two or three photolithography processes and two spacer formation processes. In addition, node separation regions of the conductive lines may be easily formed without a misalignment problem.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/964,624, filed Dec. 10, 2015 (now U.S. Pat. No. 9,761,603, issuedSep. 12, 2017), which itself claims priority under 35 U.S.C. § 119 toKorean Patent Application No. 10-2014-0190608, filed on Dec. 26, 2014 inthe Korean intellectual Property Office, the disclosure of which ishereby incorporated by reference in its entirety.

BACKGROUND

The inventive concepts relate to methods for fabricating a semiconductordevice and semiconductor devices fabricated by the same.

A double patterning technique may be used to form patterns having apitch that is smaller than the minimum pitch that may be realized by anexposure apparatus. For example, spacers may be formed on both sidewallsof a sacrificial pattern formed using a photolithography process, and anetch target layer may be etched using the spacers as each masks to formfine patterns. However, as semiconductor devices have been highlyintegrated, new techniques capable of forming finer patterns have beendemanded.

SUMMARY

Embodiments of the inventive concepts may provide methods forfabricating a semiconductor device capable of reducing or eliminating amisalignment problem and of simply forming fine patterns.

Embodiments of the inventive concepts may also provide semiconductordevices having improved reliability and integration density.

In one aspect, a method for fabricating a semiconductor device mayinclude: sequentially forming an etch target layer, a lower mold layer,and an intermediate mold layer on a substrate, the etch target layerincluding a separation region; forming first mold patterns on theintermediate mold layer; forming first spacers on sidewalls of the firstmold patterns; etching the intermediate mold layer using the firstspacers as etch masks to form second mold patterns; forming secondspacers on sidewalls of the second mold patterns; etching the lower moldlayer using the second spacers as etch masks to form third moldpatterns; forming a fourth mold pattern that at least partially coversat least one of the third mold patterns, the fourth mold patternvertically overlapping the separation region; etching the etch targetlayer using the fourth mold pattern and ones of the third mold patternsthat are exposed by the fourth mold pattern as etch masks to forminsulating patterns; and forming conductive lines in spaces between theinsulating patterns.

In an embodiment, the substrate may include a cell array region and aperipheral circuit region, and the separation region may be on the cellarray region. The fourth mold pattern may include a plurality of fourthmold patterns, and a one of the fourth mold patterns that is on theperipheral circuit region may expose a portion of the etch target layerthat is on the peripheral circuit region.

In an embodiment, the first, second and third mold patterns may beformed on the cell array region.

In an embodiment, forming the first mold patterns may include: formingan upper mold layer on the intermediate mold layer; forming photoresistpatterns on the upper mold layer, the photoresist patterns covering theupper mold layer of the peripheral circuit region but exposing portionsof the upper mold layer of the cell array region; and etching the uppermold layer using the photoresist patterns as etch masks to form thefirst mold patterns on the cell array region.

In an embodiment, the portion of the lower mold layer that is on theperipheral circuit region may be completely etched when the third moldpatterns are formed.

In an embodiment, forming the fourth mold patterns may include: forminga preliminary mold layer on the third mold patterns; forming photoresistpatterns on the preliminary mold layer; and etching the preliminary moldlayer using the photoresist patterns as etch masks to form fourth moldpatterns. The photoresist pattern on the cell array region mayvertically overlap the separation region.

In an embodiment, the third mold patterns may include a first extensionpattern and a second extension pattern that extend in parallel to eachother in one direction, and one sidewall of the fourth mold pattern maybe disposed between the first extension pattern and the second extensionpattern.

In an embodiment, etching the etch target layer to form the insulatingpatterns may include: etching a portion of the etch target layer, whichis exposed by the fourth mold pattern between the first and secondextension patterns, to form a dummy trench.

In an embodiment, a width of a portion of the dummy trench may besubstantially equal to a maximum width of the first spacer, and a widthof another portion of the dummy trench may be smaller than the maximumwidth of the first spacer.

In an embodiment, forming the conductive lines may include: forming adummy interconnection in the dummy trench. The dummy interconnection maybe between the separation region and a first of the insulating patternsthat is adjacent the separation region.

In an embodiment, the method may further include: forming a first masklayer on the intermediate mold layer before forming the first moldpatterns; and etching the first mask layer using the first spacers asetch masks to form first mask patterns. The first mask patterns may bealso used as etch masks when the intermediate mold layer is etched.

In an embodiment, a width of at least one of the first mold patterns maybe about three times a maximum width of one of the first spacers.

In an embodiment, a distance between adjacent ones of the first moldpatterns may be about five times a maximum width of one of the firstspacers.

In an embodiment, a width of at least one of the second mold patternsand a width of the third mold pattern may be substantially equal to amaximum width of one of the first spacers.

In an embodiment, a distance between adjacent ones of the second moldpatterns may be about three times a maximum width of one of the firstspacers.

In an embodiment, a distance between adjacent ones of the third moldpatterns may be substantially equal to a maximum width of one of thefirst spacers.

In an embodiment, a maximum width of at least one of the second spacersmay be substantially equal to a maximum width of one of the firstspacers.

In another aspect, a semiconductor device may include: insulatingpatterns on a substrate; and a plurality of conductive lines in spacesbetween the insulating patterns, the conductive lines extending parallelto each other. The conductive lines may include a first dummyinterconnection, a second dummy interconnection, and cellinterconnections disposed between the first and second dummyinterconnections. The insulating patterns may include a separationinsulating pattern. The first and second dummy interconnections may bespaced apart from each other with the separation insulating patterninterposed therebetween.

In an embodiment, a width of a portion of the first dummyinterconnection may be substantially equal to a width of each of thecell interconnections, and a width of a portion of the second dummyinterconnection may be substantially equal to the width of each of thecell interconnections, and a width of another portion of the first dummyinterconnection may be smaller than the width of the cellinterconnection and a width of another portion of the second dummyinterconnection may be smaller than the width of the cellinterconnection.

In an embodiment, a distance between the first dummy interconnection anda first of the cell interconnections that is adjacent the first dummyinterconnection is substantially equal to a width of the cellinterconnection, and a distance between the second dummy interconnectionand a second of the cell interconnections that is adjacent the seconddummy interconnection may be substantially equal to the width of thecell interconnection.

In an embodiment, the substrate may include a cell array region and aperipheral circuit region, and the conductive lines may further include:a peripheral interconnection on the peripheral circuit region.

In still another aspect, a method for fabricating a semiconductor devicemay include: sequentially forming an etch target layer and a lower moldlayer on a substrate, the etch target layer including a separationregion; forming a first etch stop pattern on the lower mold layer, thefirst etch stop pattern vertically overlapping the separation region;forming an intermediate mold layer on the lower mold layer, theintermediate mold layer at least partially covering the first etch stoppattern; forming first mold patterns on the intermediate mold layer;forming first spacers on sidewalls of the first mold patterns; etchingthe intermediate mold layer using the first spacers as etch masks toform second mold patterns, where portions of the second mold patternsare on the first etch stop pattern; forming second spacers on sidewallsof the second mold patterns; etching portions of the first etch stoppattern to form second etch stop patterns during the formation of thesecond spacers; etching the lower mold layer using the second spacersand the second etch stop patterns as etch masks to form third moldpatterns; etching the etch target layer using the third mold patterns asetch masks to form insulating patterns; and forming conductive lines inspaces between the insulating patterns.

In an embodiment, a pair of the second spacers may be disposed onrespective ones of the second etch stop patterns, and outer sidewalls ofeach pair of second spacers may be coplanar with outer sidewalls ofrespective ones of the second etch stop patterns. A distance betweenadjacent ones of the pairs of second spacers may be substantially equalto a maximum width of the second spacer.

In an embodiment, forming the first etch stop pattern may include:sequentially forming an etch stop layer and a preliminary mold layer onthe lower mold layer; forming a first photoresist pattern on thepreliminary mold layer; etching the preliminary mold layer using thefirst photoresist pattern as an etch mask to form a fourth mold pattern;and etching the etch stop layer using the fourth mold pattern as an etchmask to form the first etch stop pattern. The first photoresist patternmay vertically overlap the separation region.

In an embodiment, the substrate may include a cell array region and aperipheral circuit region, and the separation region may be on the cellarray region.

In an embodiment, the first etch stop pattern may include a plurality offirst etch stop patterns, and one of the first etch stop patterns thatis on the peripheral circuit region may expose a portion of the lowermold layer that is on the peripheral circuit region.

In an embodiment, the first and second mold patterns may be formed onthe cell array region, and the one of the first etch stop patterns thatis on the peripheral circuit region may remain when the second etch stoppatterns are formed on the cell array region.

In an embodiment, forming the first mold patterns may include: formingan upper mold layer on the intermediate mold layer; forming secondphotoresist patterns on the upper mold layer, the second photoresistpatterns covering the portions of the upper mold layer that are on theperipheral circuit region but exposing portions of the upper mold layerof the cell array region; and etching the upper mold layer using thesecond photoresist patterns as etch masks to form the first moldpatterns on the cell array region.

In an embodiment, forming the first spacers may include: forming a firstspacer layer covering the first mold patterns; forming a thirdphotoresist pattern covering portions of the first spacer layer that areon the peripheral circuit region, the third photoresist pattern exposingat least a portion of the first spacer layer that is on the cell arrayregion; and anisotropically etching the first spacer layer using thethird photoresist pattern as an etch mask to form the first spacers.

In an embodiment, the method may further include: forming a first masklayer on the intermediate mold layer before forming the first moldpatterns; and etching the first mask layer using the first spacers asetch masks to form first mask patterns. The first mask patterns may bealso used as etch masks when the intermediate mold layer is etched, andthe first mask patterns may remain on the second mold patterns after theformation of the second mold patterns.

In an embodiment, forming the second spacers and the second etch stoppatterns may include: forming a second spacer layer on the second moldpatterns and the first mask patterns; anisotropically etching the secondspacer layer until the first mask patterns are exposed, thereby formingthe second spacers; and anisotropically etching portions of the firstetch stop pattern that are exposed by the first mask patterns, thesecond spacers and the second mold patterns to form the second etch stoppatterns.

In an embodiment, a width of at least one of the first mold patterns maybe about three times a maximum width of one of the first spacers.

In an embodiment, a distance between adjacent ones of the first moldpatterns may be about five times a maximum width of one of the firstspacers.

In an embodiment, a width of at least one of the second mold patternsmay be substantially equal to a maximum width of one of the firstspacers.

In an embodiment, a distance between adjacent ones of the second moldpatterns may be about three times a maximum width of one of the firstspacers.

In an embodiment, a maximum width of at least one of the second spacersmay be substantially equal to a maximum width of one of the firstspacers.

In an embodiment, a width of at least one of the second etch stoppatterns may be about three times a maximum width of one of the firstspacers.

In an embodiment, a distance between adjacent ones of the second etchstop patterns may be substantially equal to a maximum width of one ofthe first spacers.

In an embodiment, a width of at least one of the third mold patternsthat is on the separation region may be about three times a maximumwidth of the first spacer, and a width of one of the third mold patternsthat is adjacent the separation region may be substantially equal to themaximum width of one of the first spacers.

In an embodiment, a distance between adjacent ones of the third moldpatterns may be substantially equal to a maximum width of one of thefirst spacers.

In an embodiment, forming the first spacers may include: forming a firstspacer layer on the first mold patterns; forming a third photoresistpattern on the first spacer layer, the third photoresist patternvertically overlapping a portion of the separation region; andanisotropically etching the first spacer layer using the thirdphotoresist pattern as an etch mask to form the first spacers.

In an embodiment, a portion of the first spacer layer which is notetched by the photoresist pattern comprises a separation spacer layer.Etching the intermediate mold layer to form the second mold patterns mayinclude: etching the intermediate mold layer using the first spacers andthe separation spacer layer as etch masks to form the second moldpatterns and a separation mold pattern. The separation mold pattern maybe on the first etch stop pattern.

In an embodiment, the second etch stop patterns may include a separationetch stop pattern, and the separation etch stop pattern may verticallyoverlap the separation mold pattern and a pair of the second spacerscovering opposed sidewalls of the separation mold pattern.

In an embodiment, the pair of the second spacers may be on theseparation etch stop pattern, and outer sidewalls of the pair of secondspacers may be coplanar with outer sidewalls of the separation etch stoppattern. A distance between the pair of second spacers may be greaterthan a maximum width of the second spacer.

In an embodiment, a width of the separation etch stop pattern may begreater than about three times a maximum width of one of the firstspacers.

In an embodiment, the insulating patterns may include a separationinsulating pattern corresponding to the separation etch stop pattern,and the conductive lines adjacent to the separation insulating patternmay be spaced apart from each other by the separation insulatingpattern.

In yet another aspect, a semiconductor device may include: insulatingpatterns on a substrate; and a plurality of conductive lines in spacesbetween the insulating patterns, the conductive lines extending parallelto each other. The conductive lines may include a first cellinterconnection, a second cell interconnection, and a third cellinterconnection that is disposed between the first and second cellinterconnections. One end portion of the second cell interconnection mayprotrude more than one end portion of the third cell interconnection ina direction parallel to the first to third cell interconnections whenviewed in plan view. One end portion of the first cell interconnectionmay protrude more than the one end portion of the second cellinterconnection in the direction parallel to the first to third cellinterconnections when viewed in plan view.

In an embodiment, a distance between the first and second cellinterconnections may be about three times a width of the first cellinterconnection.

In an embodiment, the insulating patterns may include a separationinsulating pattern, and the conductive lines adjacent to the separationinsulating pattern may be spaced apart from each other by the separationinsulating pattern.

In an embodiment, a distance between the conductive lines respectivelyadjacent to both sidewalls of the separation insulating pattern may begreater than about three times a minimum width of the conductive lines.

In still another aspect, a method for fabricating a semiconductor devicemay include: forming an etch target layer on a substrate, the etchtarget layer including a separation region; forming a lower mold layeron the etch target layer opposite the substrate; forming an intermediatemold layer on the lower mold layer opposite the etch target layer;forming first mold patterns on the intermediate mold layer; formingfirst spacers on sidewalls of the first mold patterns, wherein a firstof the first spacers that is on a sidewall of a first of the first moldpatterns has a maximum width that is about one third a maximum width ofthe first of the first mold patterns; etching the intermediate moldlayer using the first spacers as etch masks to form second moldpatterns, wherein a first of the second mold patterns has a width thatis substantially equal to the maximum width of the first of the firstspacers; forming second spacers on sidewalls of the second moldpatterns, wherein a first of the second spacers has a width that issubstantially equal to the maximum width of the first of the firstspacers; etching the lower mold layer using at least the second spacersas etch masks to form third mold patterns; etching the etch target layerusing at least some of the third mold patterns as etch masks to formetch target layer patterns; and forming conductive lines in spacesbetween the etch target layer patterns.

In an embodiment, a distance between adjacent ones of the first moldpatterns may be about five times a maximum width of the first of thefirst spacers, and a distance between adjacent ones of the second moldpatterns may be about three times a maximum width of the first of thefirst spacers.

In some embodiments, the method may further include, after forming thethird mold patterns: forming a fourth mold pattern on at least one ofthe third mold patterns, the fourth mold pattern vertically overlappingthe separation region. In such embodiments, etching the etch targetlayer using at least some of the third mold patterns as etch masks toform etch target layer patterns may comprise etching the etch targetlayer using the fourth mold pattern and ones of the third mold patternsthat are exposed by the fourth mold pattern as etch masks to form theetch target layer patterns.

In some embodiments, the method may further include, after forming thelower mold layer but before forming the intermediate mold layer, forminga first etch stop pattern on the lower mold layer, the first etch stoppattern vertically overlapping the separation region. In suchembodiments, the intermediate mold layer may at least partially coverthe first etch stop pattern.

In some embodiments, portions of the second mold patterns may be on thefirst etch stop pattern.

In some embodiments, the method may further include, etching portions ofthe first etch stop pattern to form second etch stop patterns during theformation of the second spacers.

In some embodiments, etching the lower mold layer using at least thesecond spacers as etch masks to form third mold patterns may compriseetching the lower mold layer using the second spacers and the secondetch stop patterns as etch masks to form the third mold patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concepts will become more apparent in view of the attacheddrawings and accompanying detailed description.

FIGS. 1A to 12A are plan views illustrating a method for fabricating asemiconductor device according to some embodiments of the inventiveconcepts;

FIGS. 1B to 8B are cross-sectional views taken along lines A-A′ and B-B′of FIGS. 1A to 8A, respectively;

FIGS. 9B to 12B are cross-sectional views taken along lines A-A′, B-B′,and C-C′ of FIGS. 9A to 12A, respectively;

FIGS. 13A to 22A are plan views illustrating a method for fabricating asemiconductor device according to other embodiments of the inventiveconcepts;

FIGS. 13B to 22B are cross-sectional views taken along lines A-A′, B-B′,and C-C′ of FIGS. 13A to 22A, respectively;

FIGS. 23A and 23B are cross-sectional views illustrating a method offorming second spacers and second etch stop patterns in a method forfabricating a semiconductor device according to other embodiments of theinventive concepts;

FIGS. 24A to 29A are plan views illustrating a method for fabricating asemiconductor device according to still other embodiments of theinventive concepts;

FIGS. 24B to 29B are cross-sectional views taken along lines A-A′, B-B′,and C-C′ of FIGS. 24A to 29A, respectively;

FIG. 30 is a schematic block diagram illustrating an embodiment of anelectronic system including a semiconductor device according toembodiments of the inventive concepts;

FIG. 31 is a schematic block diagram illustrating an embodiment of amemory card including a semiconductor device according to embodiments ofthe inventive concepts; and

FIG. 32 is a schematic block diagram illustrating an embodiment of aninformation processing system including a semiconductor device accordingto embodiments of the inventive concepts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The inventive concepts will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the inventive concepts are shown. The advantages and features of theinventive concepts and methods of achieving them will be apparent fromthe following exemplary embodiments that will be described in moredetail with reference to the accompanying drawings. It should be noted,however, that the inventive concepts are not limited to the followingexemplary embodiments, and may be implemented in various forms. In thedrawings, embodiments of the inventive concepts are not limited to thespecific examples provided herein and are exaggerated for clarity.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to limit the inventive concepts. Asused herein, the singular terms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. It will beunderstood that when an element is referred to as being “connected” or“coupled” to another element, it may be directly connected or coupled tothe other element or intervening elements may be present.

Similarly, it will be understood that when an element such as a layer,region or substrate is referred to as being “on” another element, it canbe directly on the other element or intervening elements may be present.In contrast, the term “directly” means that there are no interveningelements. It will be further understood that the terms “comprises”,“comprising,”, “includes” and/or “including”, when used herein, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be also understood that although the terms first, second, thirdetc. may be used herein to describe various elements, these elementsshould not be limited by these terms. These terms are only used todistinguish one element from another element. Thus, a first element insome embodiments could be termed a second element in other embodimentswithout departing from the teachings of the inventive concepts. The samereference numerals or the same reference designators denote the sameelements throughout the specification. Note that the different widths(e.g., width W7 described later herein) discussed in differentembodiments may refer to different widths in the different embodiments.

Moreover, exemplary embodiments are described herein with reference tocross-sectional illustrations and/or plane illustrations that may beidealized exemplary illustrations. Accordingly, variations from theshapes of the illustrations as a result, for example, of manufacturingtechniques and/or tolerances, are to be expected. Thus, exemplaryembodiments should not be construed as limited to the shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing. For example, an etched region that isillustrated as having vertical sidewalls will, typically, have roundedor curved features. Thus, the regions illustrated in the figures areschematic in nature and their shapes are not intended to illustrate theactual shape of a region of a device and are not intended to limit thescope of example embodiments.

Devices and methods of forming devices according to various embodimentsdescribed herein may be embodied in microelectronic devices such asintegrated circuits, wherein a plurality of devices according to variousembodiments described herein are integrated in the same microelectronicdevice. Accordingly, the cross-sectional view(s) illustrated herein maybe replicated in two different directions, which need not be orthogonal,in the microelectronic device. Thus, a plan view of the microelectronicdevice that embodies devices according to various embodiments describedherein may include a plurality of the devices in an array and/or in atwo-dimensional pattern that is based on the functionality of themicroelectronic device.

The devices according to various embodiments described herein may beinterspersed among other devices depending on the functionality of themicroelectronic device. Moreover, microelectronic devices according tovarious embodiments described herein may be replicated in a thirddirection that may be orthogonal to the two different directions, toprovide three-dimensional integrated circuits.

Accordingly, the cross-sectional view(s) illustrated herein providesupport for a plurality of devices that extend along two differentdirections in a plan view and/or in three different directions in aperspective view. For example, when a single active region isillustrated in a cross-sectional view of a device/structure, thedevice/structure may include a plurality of active regions andtransistor structures (or memory cell structures, gate structures, etc.,as appropriate to the case) thereon, as would be illustrated by a planview of the device/structure.

FIGS. 1A to 12A are plan views illustrating a method for fabricating asemiconductor device according to some embodiments of the inventiveconcepts. FIGS. 1B to 8B are cross-sectional views taken along linesA-A′ and B-B′ of FIGS. 1A to 8A, respectively. FIGS. 9B to 12B arecross-sectional views taken along lines A-A′, B-B′, and C-C′ of FIGS. 9Ato 12A, respectively.

Referring to FIGS. 1A and 1B, an interlayer insulating layer 3, an etchtarget layer 5, a lower mold layer 7, an intermediate mold layer 17, afirst mask layer 19, an upper mold layer 27, and a second mask layer 29may be sequentially formed on a substrate 1.

The substrate 1 may include a cell array region CR and a peripheralcircuit region PR. Although not shown in the drawings, a plurality oftransistors may be formed on the cell array region CR of the substrate1. The interlayer insulating layer 3 may be a silicon oxide layer thatcovers the transistors. A plurality of contacts (not shown) maypenetrate the interlayer insulating layer 3 so as to be connected to thetransistors. The substrate 1 may be a single-crystalline silicon waferor a silicon-on-insulator (SOI) substrate.

The portion of the etch target layer 5 that is disposed on the cellarray region CR may include a separation region SA. The separationregion SA may be defined as a region in which conductive lines 51, 53 a,53 b and 55 that are described later herein are not formed. Since theconductive lines 51, 53 a, 53 b and 55 are not formed in the separationregion SA, node separation may be realized through the separation regionSA.

For example, the etch target layer 5 may be a silicon oxide layer, asilicon oxynitride layer, a silicon nitride layer, or a plasma-enhancedoxide (PE-oxide) layer. The lower mold layer 7 may be a poly-siliconlayer. The intermediate mold layer 17 and the upper mold layer 27 may bethe same material. For example, the intermediate mold layer 17 and theupper mold layer 27 may each be a spin-on-hardmask (SOH) layer or aspin-on-carbon (SOC) layer. The first and second mask layers 19 and 29may be the same material. For example, the first and second mask layers19 and 29 may be a silicon oxynitride layer.

First photoresist patterns PP1 may be formed on the second mask layer29. The first photoresist pattern PP1 of the peripheral circuit regionPR may completely cover the second mask layer 29 of the peripheralcircuit region PR when viewed in plan view. The first photoresistpatterns PP1 disposed on the cell array region CR may define firstopenings OP1. The first openings OP1 may expose portions of a topsurface of the second mask layer 29. The first photoresist patterns PP1of the cell array region CR may define outlines of the conductive lines51, 53 a, 53 b and 55 that are described later herein.

Referring again to FIG. 1B, a width W1 of one or more of the firstphotoresist patterns PP1 may be about three times the maximum width W2of a first spacer 31 p that will be described later. A distance L1between adjacent ones of the first photoresist patterns PP1 may be aboutfive times the maximum width W2 of the first spacer 31P.

Referring to FIGS. 2A and 2B, the second mask layer 29 may be etchedusing the first photoresist patterns PP1 as etch masks to form secondmask patterns 29 p. Shapes of the second mask patterns 29P maycorresponding to those of the first photoresist patterns PP1 when viewedin plan view. The second mask layer 29 disposed on the peripheralcircuit region PR may not be etched but may remain.

Next, the upper mold layer 27 may be etched using the second maskpatterns 29P as etch masks to form first mold patterns 27 p. Shapes ofthe first mold patterns 27 p may correspond to those of the second maskpatterns 29 p when viewed in plan view. The first mold patterns 27 p mayexpose portions of a top surface of the first mask layer 19 throughopenings defined between the first mold patterns 27 p. The upper moldlayer 27 disposed on the peripheral region PR may not be etched but mayremain.

The first photoresist patterns PP1 may be completely removed during theformation of the first mold patterns 27 p, so top surfaces of the secondmask patterns 29 p may be exposed. Alternatively, the first photoresistpatterns PP1 may be removed before the formation of the first moldpatterns 27 p. Portions of the second mask patterns 29 p may be etchedduring the formation of the first mold patterns 27 p.

Referring to FIGS. 3A and 3B, a first spacer layer 31 may be conformallyformed on an entire top surface of the substrate 1. In some embodiments,the first spacer layer 31 may be formed of a material having an etchselectivity with respect to the first mask layer 19, the upper moldlayer 27 and the second mask layer 29. For example, the first spacerlayer 31 may include a silicon oxide layer which is formed by an atomiclayer deposition (ALD) method. A thickness T1 of the first spacer layer31 may be substantially equal to the maximum width W2 of the firstspacer 31 p that is described later.

Referring to FIGS. 4A and 4B, the first spacer layer 31 may beanisotropically etched to form first spacers 31P which cover sidewallsof the first mold patterns 27 p. The maximum width W2 of the firstspacer 31 p may correspond to a width of a bottom surface of the firstspacer 31 p. The maximum width W2 of each of the first spacers 31 p maybe defined as ‘1F’.

Subsequently, the second mask patterns 29 p may be selectively etched toexpose top surfaces of the first mold patterns 27 p. Meanwhile, theportion of the second mask layer 29 that is disposed on the peripheralcircuit region PR may be selectively removed to expose a top surface ofthe upper mold layer 27 of the peripheral circuit region PR.

Referring to FIGS. 5A and 5B, the first mold patterns 27 p of the cellarray region CR and the upper mold layer 27 of the peripheral circuitregion PR may be selectively removed to expose a top surface of thefirst mask layer 19 and the first spacers 31 p. If the upper mold layer27 is an SOH layer, the first mold patterns 27 p and the upper moldlayer 27 may be removed by an ashing process using oxygen.

Referring to FIGS. 6A and 6B, the first mask layer 19 may be etchedusing the first spacers 31 p as etch masks to form first mask patterns19 p on the cell array region CR. Shapes of the first mask patterns 19 pmay correspond to those of the first spacers 31 p when viewed in planview. The first mask layer 19 may be completely removed in theperipheral circuit region PR.

Next, the intermediate mold layer 17 may be etched using the first maskpatterns 19 p as etch masks to form second mold patterns 17 p. Shapes ofthe second mold patterns 17 p may correspond to those of the first maskpatterns 19 p when viewed in plan view. The second mold patterns 17 pmay expose portions of a top surface of the lower mold layer 7 throughopenings defined between the second mold patterns 17 p. The intermediatemold layer 17 may be completely removed in the peripheral circuit regionPR to expose a top surface of the lower mold layer 7 in the peripheralcircuit region PR.

A width W3 of each of the second mold patterns 17 p may be substantiallyequal to the maximum width W2 of the first spacer 31 p (e.g., W3=1F). Adistance L2 between adjacent ones of the second mold patterns 17 p maybe about three times the maximum width W2 of the first spacer 31 p(e.g., L2=3F).

Referring to FIGS. 7A and 7B, a second spacer layer may be conformallyformed on an entire top surface of the substrate 1. The second spacerlayer may comprise a material having an etch selectivity with respect tothe intermediate mold layer 17 and the lower mold layer 7. For example,the second spacer layer may include a silicon oxide layer which isformed by an ALD method.

Subsequently, the second spacer layer may be anisotropically etched toform second spacers 33 p covering sidewalls of the second mold patterns17 p. The maximum width W4 of each of the second spacers 33 p may besubstantially equal to the maximum width W2 of the first spacer 31 p(e.g., W4=1F). A distance L3 between adjacent ones of the second spacers33 p may be substantially equal to the maximum width W2 of the firstspacer 31 p (e.g., L3=1F).

The first mask patterns 19 p may be selectively removed to expose topsurfaces of the second mold patterns 17 p. In addition, the second moldpatterns 17 p may be removed. Since the second mold patterns 17 p areselectively removed, a top surface of the lower mold layer 7 and thesecond spacers 33 p may be exposed. If the intermediate mold layer 17 isan SOH layer, the second mold patterns 17 p may be removed by an ashingprocess using oxygen.

The lower mold layer 7 may have an etch selectivity with respect to thesecond spacer layer, the first mask patterns 19 p and the second moldpatterns 17 p. Thus, the lower mold layer 7 may remain on the cell arrayregion CR and the peripheral circuit region PR during the formation ofthe second spacers 33 p.

Referring to FIGS. 8A and 8B, the lower mold layer 7 may be etched usingthe second spacers 33 p as etch masks to form third mold patterns 7 p onthe cell array region CR. Shapes of the third mold patterns 7 p maycorrespond to those of the second spacers 33 p when viewed in plan view.The third mold patterns 7 p may expose portions of a top surface of theetch target layer 5 through openings defined between the third moldpatterns 7 p. The lower mold layer 7 may be removed in the peripheralcircuit region PR to completely expose a top surface of the etch targetlayer 5 in the peripheral circuit region PR.

A width W5 of each of the third mold patterns 7 p may be substantiallyequal to the maximum width W2 of the first spacer 31 p (e.g., W5=1F). Adistance L4 between adjacent ones of the third mold patterns 7 p may besubstantially equal to the maximum width W2 of the first spacer 31 p(e.g., L4=1F).

Referring to FIGS. 9A and 9B, a preliminary mold layer 37 may be formedto cover the third mold patterns 7 p, and a preliminary mask layer 39may be formed on the preliminary mold layer 37. In the peripheralcircuit region PR, the preliminary mold layer 37 may cover a top surfaceof the lower mold layer 7. For example, the preliminary mold layer 37may be an SOH layer or an SOC layer. The preliminary mask layer 39 maybe a silicon oxynitride layer.

Second photoresist patterns PP2 may be formed on the preliminary masklayer 39. The second photoresist patterns PP2 may define second openingsOP2. The second openings OP2 may expose portions of a top surface of thepreliminary mask layer 39.

At least one of the second photoresist patterns PP2 may verticallyoverlap with the separation region SA when viewed in plan view (i.e., aline can be drawn that is perpendicular to the bottom surface of thesubstrate 1 that bisects at least one of the second photoresist patternsPP2 and the separation region SA). The second opening OP2 of the cellarray region CR may define the conductive lines 51, 53 a, 53 b and 55that are described later herein. The second openings OP2 of theperipheral circuit region PR may define peripheral interconnections 55that are also described later herein.

Referring to FIGS. 10A and 10B, the preliminary mask layer 39 may beetched using the second photoresist patterns PP2 as etch masks to formpreliminary mask patterns 39 p. Shapes of the preliminary mask patterns39 p may correspond to those of the second photoresist patterns PP2 whenviewed in plan view.

Subsequently, the preliminary mold layer 37 may be etched using thepreliminary mask patterns 39 p as etch masks to form fourth moldpatterns 37 p in the cell array region CR and the peripheral circuitregion PR. Shapes of the fourth mold patterns 37 p may correspond tothose of the preliminary mask patterns 39 p when viewed in plan view.

The fourth mold patterns 37 p may include third openings OP3. The thirdopenings OP3 may overlap with the second openings OP2 described abovewhen viewed in plan view. The third openings OP3 may expose portions ofthe top surface of the etch target layer 5.

In some embodiments, the third mold patterns 7 p may include a firstextension pattern ep1 and a second extension pattern ep2 that extend inparallel to each other along a first direction D1. The first and secondextension patterns ep1 and ep2 may be adjacent one sidewall 37 pw of thefourth mold pattern 37 p that is disposed on the separation region SA.The first and second extension patterns ep1 and ep2 may be spaced apartfrom each other in a second direction D2 that intersects the firstdirection D1. The sidewall 37 pw of the fourth mold pattern 37 p may bedisposed between the first and second extension patterns ep1 and ep2when viewed in plan view.

In other embodiments, even though not shown in the drawings, the fourthmold pattern 37 p may be misaligned such that the one sidewall 37 pw ofthe fourth mold pattern 37 p may be disposed on the first extensionpattern ep1 or the second extension pattern ep2. However, a second dummyinterconnection 53 b described later may be formed in a region betweenthe first and second extension patterns ep1 and ep2 when viewed in planview. Thus, even though the fourth mold pattern 37 p is misaligned, cellinterconnections 51 between first and second dummy interconnections 53 aand 53 b that are described later may be completely separated from othercell interconnections 51 that are spaced apart from the cellinterconnections 51 with the first and second dummy interconnections 53a and 53 b. In other words, it is possible to secure an alignment marginof a photolithography process used for node separation of the cellinterconnections 51.

Referring to FIGS. 11A and 11B, the etch target layer 5 may be etchedusing the preliminary mask patterns 39 p, the fourth mold patterns 37 p,and the third mold patterns 7 p as etch masks to form insulatingpatterns 5 p. The preliminary mask patterns 39 p and the fourth moldpatterns 37 p may be removed during the formation of the insulatingpatterns 5 p. The third mold patterns 7 p that are exposed by the fourthmold patterns 37 p may be partially etched during the removal of thepreliminary mask patterns 39 p and the fourth mold patterns 37 p, soportions of the third mold patterns 7 p exposed by the fourth moldpatterns 37 p may remain on the insulating patterns 5 p.

Portions of a top surface of the interlayer insulating layer 3 areexposed through the openings in the insulating patterns 5 p. Shapes ofthe insulating patterns 5 p may correspond to those of the third andfourth mold patterns 7 p and 37 p when viewed in plan view. Theinsulating patterns 5 p may include a separation insulating pattern 5ps. A shape of the separation insulating pattern 5 ps may correspond tothat of the fourth mold pattern 37 p that was disposed on the separationregion SA and then subsequently removed. In other words, the separationinsulating pattern 5 ps may substantially correspond to the separationregion SA.

In more detail, a portion of the etch target layer 5 between the firstand second extension patterns ep1 and ep2 may be etched to form a dummytrench 5 t. In other words, the etch target layer 5 between the secondextension pattern ep2 and the portion of the fourth mold pattern 37 pthat is disposed on the separation region SA may be etched to form thedummy trench 5 t. The dummy trench 5 t may define one sidewall of theseparation insulating pattern 5 ps. In addition, another dummy trench 5t may be formed to define an opposite sidewall of the separationinsulating pattern 5 ps. In other words, a pair of the dummy trenches 5t may be formed at both sides of the separation insulating pattern 5 ps,respectively.

Widths W6 of other insulating patterns 5 p other than the separationinsulating pattern 5 ps may be substantially equal to the maximum widthW2 of the first spacer 31 p (e.g., W6=1F). A distance between L5 betweenadjacent ones of the insulating patterns 5 p may be substantially equalto the maximum width W2 of the first spacer 31 p (e.g., L5=1F). A widthL5 of a portion of the dummy trench 5 t may be substantially equal tothe maximum width W2 of the first spacer 31 p (see the cross-sectionalview of the line C-C′ of FIG. 11B). On the contrary, a width L6 ofanother portion of the dummy trench 5 t that is adjacent the separationinsulating pattern 5 ps may be smaller than the maximum width W2 of thefirst spacer 31 p (see the cross-sectional view of the line A-A′ of FIG.11B).

The insulating patterns 5 p may also be formed on the peripheral circuitregion PR. The insulating patterns 5 p of the peripheral circuit regionPR may expose a portion of the top surface of the interlayer insulatinglayer 3 through an opening therebetween.

Referring to FIGS. 12A and 12B, conductive lines 51, 53 a, 53 b and 55may be formed to fill spaces between the insulating patterns 5 p. Theconductive lines 51, 53 a, 53 b and 55 may include cell interconnections51, first and second dummy interconnections 53 a and 53 b, andperipheral interconnections 55. The conductive lines 51, 53 a, 53 b and55 may include at least one of doped poly-silicon, a metal nitride(e.g., titanium nitride or tantalum nitride), or a metal material (e.g.,titanium, tantalum, tungsten, copper, or aluminum). In some embodiments,if the conductive lines 51, 53 a, 53 b and 55 include copper, theconductive lines 51, 53 a, 53 b and 55 may be formed by a damasceneprocess.

The peripheral interconnections 55 may fill the spaces between theinsulating patterns 5 p in the peripheral circuit region PR.

The conductive lines 51, 53 a, 53 b and 55 may be formed by forming thefirst and second dummy interconnections 53 a and 53 b to fill the dummytrenches 5 t. As described above, the pair of dummy trenches 5 t maydefine both sidewalls of the separation insulating pattern 5 ps. Thus,the first dummy interconnection 53 a may be adjacent one sidewall of theseparation insulating pattern 5 ps, and the second dummy interconnection53 b may be adjacent another sidewall of the separation insulatingpattern 5 ps. In other words, the first and second dummyinterconnections 53 a and 53 b may be spaced apart from each other withthe separation insulating pattern 5 ps interposed therebetween.

A width W7 of each of the cell interconnections 51 disposed between thefirst and second dummy interconnections 53 a and 53 b may besubstantially equal to the maximum width W2 of the first spacer 31 p(e.g., W7=1F). A distance L7 between adjacent ones of the cellinterconnections 51 may be substantially equal to the maximum width W2of the first spacer 31 p (e.g., L7=1F). Alternatively, a width of aportion of the cell interconnections 51 may be greater than the maximumwidth W2 of the first spacer 31 p. However, the inventive concepts arenot limited thereto.

A width W7 of a portion of each of the first and second dummyinterconnections 53 a and 53 b may be substantially equal to the maximumwidth W2 of the first spacer 31 p (see the cross-sectional view of theline C-C′ of FIG. 12B). On the contrary, a width W8 of another portionof each of the first and second dummy interconnections 53 a and 53 b maybe smaller than the maximum width W2 of the first spacer 31 p (see thecross-sectional view of the line A-A′ of FIG. 12B). The portion havingthe width W7 may be spaced apart from the separation insulating pattern5 ps, and the portion having the width W8 may be adjacent the separationinsulating pattern 5 ps.

The cell interconnections 51 may be bit lines connected to the contacts(not shown) that penetrate the interlayer insulating layer 3. However,the first and second dummy interconnections 53 a and 53 b may not beconnected to the contacts.

In the method for fabricating the semiconductor device according to someembodiments of the inventive concepts, conductive lines 51, 53 a, 53 band 55 may be formed that have a fine pitch that is smaller than theminimum pitch realized by an exposure process. The conductive lines 51,53 a, 53 b and 55 may be formed using two photolithography processes andtwo spacer formation processes. In addition, the separation region SA ofthe cell interconnections 51 may be defined simultaneously with theperipheral interconnections 55 in a second photolithography process thatdefines the peripheral interconnections 55, so the fabricating processesmay be simplified. Furthermore, since the first and second dummyinterconnections 53 a and 53 b are formed to be adjacent the bothsidewalls of the separation region SA, it is possible to secure thealignment margin of the photolithography process used for nodeseparation of the cell interconnections 51.

As shown in FIGS. 12A and 12B, in the semiconductor device according tothe present embodiment an interlayer insulating layer 3 may be providedon a substrate 1. Insulating patterns 5 p and conductive lines 51, 53 a,53 b and 55 filling spaces between the insulating patterns 5 p may bedisposed on the interlayer insulating layer 3. The substrate 1 mayinclude a cell array region CR and a peripheral circuit region PR. Theinsulating patterns 5 p may include a separation insulating pattern 5 psdisposed on the cell array region CR.

The conductive lines 51, 53 a, 53 b and 55 may include cellinterconnections 51 and first and second dummy interconnections 53 a and53 b which are disposed on the cell array region CR. In addition, theconductive lines 51, 53 a, 53 b and 55 may also include peripheralinterconnections 55 disposed on the peripheral circuit region PR. Thecell interconnections 51 may correspond to bit lines connected tocontacts (not shown) penetrating the interlayer insulating layer 3. Insome embodiments, the cell interconnections 51 may correspond to bitlines of an NAND flash memory device. The first and second dummyinterconnections 53 a and 53 b may be spaced apart from each other withthe separation insulating pattern 5 ps interposed therebetween.

A width W7 of each of the cell interconnections 51 disposed between thefirst and second dummy interconnections 53 a and 53 b may be 1F (W7=1F).A distance L7 between adjacent ones of the cell interconnections 51 maybe substantially equal to the width W7 of the cell interconnections 51(e.g., L7=1F). On the other hand, a width of a portion of the cellinterconnections 51 may be greater than 1F. However, the inventiveconcepts are not limited thereto.

A width W7 of a portion of each of the first and second dummyinterconnections 53 a and 53 b may be substantially equal to the widthW7 of the cell interconnection 51 (see the cross-sectional view of theline C-C′ of FIG. 12B). A width W8 of another portion of each of thefirst and second dummy interconnections 53 a and 53 b may be smallerthan the width W7 of the cell interconnection 51 (see thecross-sectional view of the line A-A′ of FIG. 12B). The portion havingthe width W7 may be spaced apart from the separation insulating pattern5 ps, and the portion having the width W8 may be adjacent the separationinsulating pattern 5 ps.

FIGS. 13A to 22A are plan views illustrating a method for fabricating asemiconductor device according to embodiments of the inventive concepts.FIGS. 13B to 22B are cross-sectional views taken along lines A-A′, B-B′,and C-C′ of FIGS. 13A to 22A, respectively. In the present embodiment,the same elements as described with reference to FIGS. 1A to 12A and 1Bto 12B will be indicated by the same reference numerals or the samereference designators. For the purpose of ease and convenience inexplanation, the descriptions to the same elements as in the firstembodiment of FIGS. 1A to 12A and 1B to 12B will be omitted or mentionedbriefly.

Referring to FIGS. 13A and 13B, an interlayer insulating layer 3, anetch target layer 5, a lower mold layer 7, an etch stop layer 8, apreliminary mold layer 37, and a preliminary mask layer 39 may besequentially formed on a substrate 1.

The substrate 1 may include a cell array region CR and a peripheralcircuit region PR. Even though not shown in the drawings, a plurality oftransistors may be formed on the cell array region CR of the substrate1. A plurality of contacts (not shown) may penetrate the interlayerinsulating layer 3 to connect to the transistors. The portion of theetch target layer 5 that is disposed on the cell array region CR mayinclude a separation region SA. The separation region SA may be definedas a region in which conductive lines 51 and 55 that are described laterherein are not formed.

In some embodiments, the etch stop layer 8 and the preliminary masklayer 39 may comprise the same material. For example, each of the etchstop layer 8 and the preliminary mask layer 39 may each be a siliconoxynitride layer. The preliminary mold layer 37 may be an SOH layer oran SOC layer.

First photoresist patterns PP1 may be formed on the preliminary masklayer 39. The first photoresist patterns PP1 may include first openingsOP1. The first openings OP1 may expose portions of a top surface of thepreliminary mask layer 39.

A portion of the first photoresist patterns PP1 may overlap with theseparation region SA when viewed in plan view. The first opening OP1 onthe cell array region CR may define a region in which conductive lines51 that are described later herein will be formed, and the first openingOP1 on the peripheral circuit region PR may define a region in which aperipheral interconnection 55 that is described later herein will beformed.

Referring to FIGS. 14A and 14B, the preliminary mask layer 39 may beetched using the first photoresist patterns PP1 as etch masks to formpreliminary mask patterns (see 39 p of FIGS. 10A and 10B). Next, thepreliminary mold layer 37 may be etched using the preliminary maskpatterns 39 p as etch masks to form fourth mold patterns (see 37 p ofFIGS. 10A and 10B).

Next, the etch stop layer 8 may be etched using the preliminary maskpatterns 39 p and the fourth mold patterns 37 p as etch masks to formfirst etch stop patterns 8 p. As a result, shapes of the first etch stoppatterns 8 p may correspond to those of the first photoresist patternsPP1 when viewed in plan view.

Referring to FIGS. 15A and 15B, an intermediate mold layer 17 coveringthe first etch stop patterns 8 p may be formed on the lower mold layer7. Subsequently, a first mask layer 19, an upper mold layer 27, and asecond mask layer 29 may be sequentially formed on the intermediate moldlayer 17. Second photoresist patterns PP2 may be formed on the secondmask layer 29. The second photoresist pattern PP2 of the peripheralcircuit region PR may completely cover the second mask layer 29 of theperipheral circuit region PR. The second photoresist patterns PP2 mayinclude second openings QP2 on the cell array region CR.

A width W1 of a portion of the second photoresist patterns PP2 may beabout three times the maximum width W2 of a first spacer 31 p to bedescribed later. A distance L1 between adjacent ones of the secondphotoresist patterns PP2 may be about five times the maximum width W2 ofthe first spacer 31 p.

Referring to FIGS. 16A and 16B, the second mask layer 29 and the uppermold layer 27 may be etched using the second photoresist patterns PP2 asetch masks to form second mask patterns 29 p and first mold patterns 27p. The second mask layer 29 of the peripheral circuit region PR may notbe etched but may remain (see FIGS. 2A and 2B).

Next, a first spacer layer 31 may be conformally formed on an entire topsurface of the substrate 1. A thickness T1 of the first spacer layer 31may be substantially equal to the maximum width W2 of the first spacer31 p that is described later herein.

Referring to FIGS. 17A and 17B, a third photoresist pattern PP3 having athird opening OP3 may be formed on the first spacer layer 31. The thirdopening OP3 may be disposed on the cell array region CR. In other words,the third photoresist pattern PP3 may cover the first spacer layer 31 ofthe peripheral circuit region PR but may expose a portion of the firstspacer layer 31 of the cell array region CR.

The third photoresist pattern PP3 may also cover end portions of thefirst mold patterns 27 p that are disposed on the cell array region CR.Similarly to the first opening OP1, the third opening OP3 may define aregion in which cell interconnections 51 will be formed.

Referring to FIGS. 18A and 18B, the first spacer layer 31 may beanisotropically etched using the third photoresist pattern PP3 as anetch mask to form first spacers 31 p. The first spacers 31 p may coversidewalls of the first mold patterns 27 p that are exposed through thethird opening OP3. The maximum width W2 of each of the first spacers 31p may be defined as 1F.

Subsequently, the second mask patterns 29 p that are exposed through thethird opening OP3 may be selectively removed to expose top surfaces ofthe first mold patterns 27 p. Then, the first mold patterns 27 p may beremoved.

The first spacer 31, the second mask layer 29, and the upper mold layer27 which are covered by the third photoresist pattern PP3 may remainunder the third photoresist pattern PP3. For example, the first spacerlayer 31, the second mask layer 29 and the upper mold layer 27 of theperipheral circuit region PR may not be etched.

Referring to FIGS. 19A and 19B, the first mask layer 19 may be etchedusing the first spacers 31 p as etch masks to form first mask patterns19 p on the cell array region CR. The first spacer layer 31 and thesecond mask layer 29 of the peripheral circuit region PR may be removed.

Next, the intermediate mold layer 17 may be etched using the first maskpatterns 19 p as etch masks to form second mold patterns 17 p. The firstetch stop pattern 8 p of the cell array region CR may be exposed throughopenings between the second mold patterns. Shapes of the second moldpatterns 17 p may correspond to those of the first spacers 31 p whenviewed in plan view. The second mold patterns 17 p may be formed in aregion exposed through the third opening OP3. The upper mold layer 27 ofthe peripheral circuit region PR may be removed to expose a top surfaceof the first mask layer 19 of the peripheral circuit region PR.

A width W3 of each of the second mold patterns 17 p may be substantiallyequal to the maximum width W2 of the first spacer 31 p (W3=1F). Adistance L2 between adjacent ones of the second mold patterns 17 p maybe equal to about three times the maximum width W2 of the first spacer31 p (L2=3F).

Referring to FIGS. 20A and 20B, second spacers 33 p may be formed tocover sidewalls of the second mold patterns 17 p. The second spacers 33p may be formed by conformally forming a second spacer layer on anentire top surface of the substrate 1, and then anisotropically etchingthe second spacer layer until the first mask patterns 19 p are exposed.

When the second spacers 33 p are formed, portions of the first etch stoppattern 8 p of the cell array region CR may also be etched. Thus, secondetch stop patterns 18 p may be formed. The second etch stop patterns 18p may be formed on the separation region SA.

FIGS. 23A and 23B are cross-sectional views illustrating a method offorming the second spacers 33 p and the second etch stop patterns 18 paccording to the present embodiment.

In more detail, as illustrated in FIG. 23A, the second spacer layer maybe anisotropically etched to form the second spacers 33 p that cover thesecond mold patterns 17 p. The first mask patterns 19 p may remain onthe second mold patterns 17 p after this etching step is completed.

Referring to FIG. 23B, the first mask patterns 19 p may beanisotropically etched to expose top surfaces of the second moldpatterns 17 p. When the first mask patterns 19 p are removed, portionsof the first etch stop pattern 8 p that are exposed through openingsbetween the second spacers 33 p may also be removed. In someembodiments, the first etch stop pattern 8 p may comprise the samematerial (e.g., silicon oxynitride) as the first mask patterns 19 p, sothe first mask patterns 19 p and the portions of the first etch stoppattern 8 p may be etched at the same time by the anisotropic etchingprocess.

Meanwhile, the first mask layer 19 of the peripheral circuit region PRmay also be removed by the anisotropic etching process, so that the topsurface of the intermediate mold layer 17 of the peripheral circuitregion PR may be exposed. However, when the second etch stop patterns 18p are formed on the cell array region CR, the first etch stop pattern 8p of the peripheral circuit region PR may be protected by theintermediate mold layer 17 and hence may remain on the lower mold layer7 in the peripheral circuit region PR.

Referring again to FIGS. 20A and 20B, the second mold patterns 17 p maybe selectively removed. The intermediate mold layer 17 of the peripheralcircuit region PR may also be removed at the same time to expose thefirst etch stop pattern 8 p of the peripheral circuit region PR.

The maximum width W4 of each of the second spacers 33 p may besubstantially equal to the maximum width W2 of the first spacer 31 p(W4=1F). A width W5 of each of the second etch stop patterns 18 p may beequal to about three times the maximum width W2 of the first spacer 31 p(W5=3F). A distance L3 between adjacent ones of the second etch stoppatterns 18 p may be substantially equal to the maximum width W2 of thefirst spacer 31 p (L3=1F).

In more detail, a pair of the second spacers 33 p may be disposed oneach of the second etch stop patterns 18 p. Outer sidewalls of the pairof second spacers 33 p may be aligned with outer sidewalls of therespective underlying second etch stop pattern 18 p. In other words, theouter sidewalls of the pair of second spacers 33 p may be coplanar withthe outer sidewalls of the second etch stop pattern 18 p. A distancebetween the pair of second spacers 33 p may be substantially equal tothe maximum width W4 of each second spacer 33 p. In the presentembodiment, the second etch stop patterns 18 p may define a region inwhich cell interconnections 51 that are described later herein areprovided.

Referring to FIGS. 21A and 21B, the lower mold layer 7 may be etchedusing the second spacers 33 p and the second etch stop patterns 18 p asetch masks to form third mold patterns 7 p. Unlike FIGS. 8A and 8B, thethird mold patterns 7 p may be formed on the peripheral circuit regionPR as well as the cell array region CR. The third mold patterns 7 p ofthe peripheral circuit region PR may define a region in which aperipheral interconnection 55 that is described later herein is formed.The third mold patterns 7 p of the cell array region CR may havedifferent widths W6 and W7 from each other depending upon theirpositions in the device structure.

In more detail, a width W6 of the third mold pattern 7 p correspondingto the second etch stop pattern 18 p may be about three times themaximum width W2 of the first spacer 31 p (W6=3F). This is because thesecond etch stop patterns 18 p are etched by the second spacers 33 p,the first mask patterns 19 p, and the second mold patterns 17 p to havethe width W5 substantially equal to 3F. For example, the width W6 of thethird mold patterns 7 p that are disposed on the separation region SAmay be about three times the maximum width W2 of the first spacer 31 p(W6=3F). A distance L4 between the third mold patterns 7 p whichcorrespond to the second etch stop patterns 18 p and are adjacent toeach other may be substantially equal to the maximum width W2 of thefirst spacer 31 p (L4=1F). A width W7 of the third mold patterns 7 poutside of the separation region SA may be substantially equal to themaximum width W2 of the first spacer 31 p (W7=1F). This is because thethird mold patterns 7 p that are outside the separation region SA areetched by the second spacers 33 p to have the width W2 substantiallyequal to 3F.

Referring to FIGS. 22A and 22B, the etch target layer 5 may be etchedusing the third mold patterns 7 p as etch masks to form insulatingpatterns 5 p. The insulating patterns 5 p may expose portions of the topsurface of the interlayer insulating layer 3 through spacestherebetween. Shapes of the insulating patterns 5 p may correspond tothose of the third mold patterns 7 p when viewed in plan view.

The insulating patterns 5 p may include separation insulating patterns 5ps formed in the separation region SA. In some embodiments, shapes ofthe separation insulating patterns 5 ps may correspond to those of thethird mold patterns 7 p formed on the separation region SA when viewedin plan view.

Conductive lines 51 and 55 may be formed to fill spaces between theinsulating patterns 5 p. The conductive lines 51 and 55 may include cellinterconnections 51 and peripheral interconnections 55. In someembodiments, if the conductive lines 51 and 55 include copper, theconductive lines 51 and 55 may be formed by a damascene process. Theperipheral interconnections 55 filling the spaces between the insulatingpatterns 5 p may be formed on the peripheral circuit region PR.

The cell interconnections 51 adjacent to the separation insulatingpatterns 5 ps may be spaced apart from each other by the separationinsulating patterns 5 ps. For example, the cell interconnections 51 inthe separation region SA may be spaced apart from each other with theseparation insulating pattern 5 ps interposed therebetween.

In more detail, the cell interconnections 51 on the cell array region CRmay include first, second and third cell interconnections 51 a, 51 b and51 c that extend in parallel to each other in a first direction D1. Thethird cell interconnection 51 c may be disposed between the first andsecond cell interconnections 51 a and 51 b. The separation insulatingpattern 5 ps may also be disposed between the first and second cellinterconnections 51 a and 51 b. One end portion 51 be of the second cellinterconnection 51 b may protrude more than one end portion 51 ce of thethird cell interconnection 51 c in the first direction D1 when viewed inplan view. One end portion 51 ae of the first cell interconnection 51 amay protrude more than the one end portion 51 be of the second cellinterconnection 51 b in the first direction D1 when viewed in plan view.

A width W8 of each of the cell interconnections 51 may be substantiallyequal to the maximum width W2 of the first spacer 31 p (W8=1F). Adistance L5 between adjacent ones of the cell interconnections 51 may besubstantially equal to the maximum width W2 of the first spacer 31 p(L5=1F). However, a distance L6 between the cell interconnections 51which are adjacent to each other with the separation insulating pattern5 ps interposed therebetween may be about three times the maximum widthW2 of the first spacer 31 p (L6=3F). For example, a distance between thefirst and second cell interconnections 51 a and 51 b may be about 3F.Meanwhile, a width of a portion of the cell interconnections 51 may begreater than the maximum width W2 of the first spacer 31 p. However, theinventive concepts are not limited thereto.

The cell interconnections 51 may correspond to bit lines that areconnected to the contacts (not shown) that penetrate the interlayerinsulating layer 3.

In the method for fabricating the semiconductor device according to thepresent embodiment, the conductive lines 51 and 55 having a fine pitchthat is smaller than the minimum pitch realized by an exposure processmay be formed using three photolithography processes and two spacerformation processes. In addition, the separation region SA of the cellinterconnections 51 may be defined by the first etch stop pattern 8 pduring a first photolithography process defining the peripheralinterconnection's 55, so the fabricating processes may be simplified.Furthermore, since the separation insulating patterns 5 ps used for nodeseparation of the cell interconnections 51 are formed to be self-alignedby the first etch stop pattern 8 p, it is possible to reduce or preventmisalignment of the cell interconnections 51.

As shown in FIGS. 22A and 22B, in the semiconductor device according tothe present embodiment, insulating patterns 5 p and conductive lines 51and 55 filling spaces between the insulating patterns 5 p may bedisposed on the substrate 1. The insulating patterns 5 p may includeseparation insulating patterns 5 ps on a cell array region CR. Theconductive lines 51 and 55 may include cell interconnections 51 disposedon the cell array region CR and peripheral interconnections 55 disposedon a peripheral circuit region PR.

The cell interconnections 51 that are adjacent the separation insulatingpatterns 5 ps may be spaced apart from each other by the separationinsulating patterns 5 ps. In particular, the cell interconnections 51disposed on the cell array region CR may include first, second and thirdcell interconnections 51 a, 51 b and 51 c that extend in parallel toeach other in a first direction D1. The third cell interconnection 51 cmay be disposed between the first and second cell interconnections 51 aand 51 b. The separation insulating pattern 5 ps may also be disposedbetween the first and second cell interconnections 51 a and 51 b. An endportion 51 be of the second cell interconnection 51 b may protrude morethan an end portion 51 ce of the third cell interconnection 51 c in thefirst direction D1 when viewed in plan view. An end portion 51 ae of thefirst cell interconnection 51 a may protrude more than theabove-referenced end portion 51 be of the second cell interconnection 51b in the first direction D1 when viewed in plan view.

A width W8 of each of the cell interconnections 51 may be substantiallyequal to 1F (W8=1F). A distance L5 between adjacent ones of the cellinterconnections 51 may be substantially equal to the width W8 of thecell interconnection 51 (L5=1F). However, a distance L6 between the cellinterconnections 51 which are adjacent to each other with the separationinsulating pattern 5 ps interposed therebetween may be about three timesthe width W8 of the cell interconnection 51 (L6=3F). For example, adistance between the first and second cell interconnections 51 a and 51b may be about 3F. Meanwhile, a width of a portion of the cellinterconnections 51 may be greater than 1F. However, the inventiveconcepts are not limited thereto.

FIGS. 24A to 29A are plan views illustrating a method for fabricating asemiconductor device according to still further embodiments of theinventive concepts. FIGS. 24B to 29B are cross-sectional views takenalong lines A-A′, B-B′, and C-C′ of FIGS. 24A to 29A, respectively. Inthe present embodiment, the same elements as described with reference toFIGS. 13A to 22A and 13B to 22B will be referred to using the samereference numerals or the same reference designators. For the purpose ofease and convenience in explanation, descriptions of elements alreadydescribed above with respect to the embodiment of FIGS. 13A to 22A and13B to 22B will be omitted or mentioned briefly.

Referring to FIGS. 24A and 24B, third photoresist patterns PP3 may beformed on the structure that is described above with reference to FIGS.16A and 16B. The third photoresist patterns PP3 may be formed on thefirst spacer layer 31 and may have a third opening OP3. The thirdopening OP3 may be disposed on the cell array region CR. In other words,the third photoresist patterns PP3 may cover the first spacer layer 31of the peripheral circuit region PR but may expose a portion of thefirst spacer layer 31 of the cell array region CR.

In the present embodiment, unlike FIGS. 17A and 17B, at least one of thethird photoresist patterns PP3 may vertically overlap a portion theseparation region SA (i.e., a line can be drawn that is perpendicular tothe bottom surface of the substrate 1 that bisects both the separationregion SA and the third photoresist patterns PP3). The third photoresistpattern PP3 disposed on the separation region SA may define a secondseparation insulating pattern 5 psb which will be described later.

Referring to FIGS. 25A and 25B, the first spacer layer 31 may beanisotropically etched using the third photoresist patterns PP3 as etchmasks to form first spacers 31 p. The first spacers 31 p may coversidewalls of the first mold patterns 27 p that are exposed through thethird opening QP3. The maximum width W2 of each of the first spacers 31p may be defined as 1F.

Subsequently, the second mask patterns 29 p exposed through the thirdopening OP3 may be selectively removed to expose top surfaces of thefirst mold patterns 27 p that are not covered by the third photoresistpatterns PP3. Next, the exposed first mold patterns 27 p may be removed.

During the above processing steps, the first spacer layer 31, the secondmask layer 29, and the upper mold layer 27 which are disposed under thethird photoresist patterns PP3 may remain on the first mask layer 19.For example, the first spacer layer 31, the second mask layer 29 and theupper mold layer 27 of the peripheral circuit region PR may not beetched. In addition, a portion of the first spacer layer 31 disposedunder the third photoresist pattern PP3 overlapping with the separationregion SA may not be etched. The portion of the first spacer layer 31which is not etched by the third photoresist pattern PP3 overlappingwith the separation region SA may be defined as a separation spacerlayer 31 s (see the cross-sectional view of the line A-A′ of FIG. 25B).The third photoresist patterns PP3 may then be removed.

Referring to FIGS. 26A and 26B, the first mask layer 19 may be etchedusing the first spacers 31 p and the separation spacer layer 31 s asetch masks to form first mask patterns 19 p and a separation maskpattern 19 ps on the cell array region CR. At this time, the firstspacer layer 31 and the second mask layer 29 of the peripheral circuitregion PR may be removed.

Next, the intermediate mold layer 17 may be etched using the first maskpatterns 19 p and the separation mask pattern 19 ps as etch masks toform second mold patterns 17 p and a first separation mold pattern 17ps.

When viewed in plan view, shapes of the second mold patterns 17 p maycorrespond to those of the first spacers 31 p and a shape of the firstseparation mold pattern 17 ps may correspond to that of the separationspacer layer 31 s. The first separation mold pattern 17 ps may be formedon the first etch stop pattern 8 p. Meanwhile, the upper mold layer 27of the peripheral circuit region PR may be removed to expose the topsurface of the first mask layer 19 of the peripheral circuit region PR.

A width W3 of each of the second mold patterns 17 p may be substantiallyequal to the maximum width W2 of the first spacer 31 p (W3=1F). Adistance L2 between adjacent ones of the second mold patterns 17 p maybe about three times the maximum width W2 of the first spacer 31 p(L2=3F). A width W4 of the first separation mold pattern 17 ps may begreater than about three times the maximum width W2 of the first spacer31 p.

Referring to FIGS. 27A and 27B, second spacers 33 p may be formed tocover sidewalls of the second mold patterns 17 p and the firstseparation mold pattern 17 ps. When the second spacers 33 p are formed,portions of the first etch stop pattern 8 p of the cell array region CRmay also be etched. Thus, second etch stop patterns 18 p may be formedon the separation region SA.

However, unlike FIGS. 23A and 23B, the first etch stop pattern 8 p underthe first separation mold pattern 17 ps may not be etched to be formedinto a separation etch stop pattern 18 ps. In other words, theseparation etch stop pattern 18 ps may overlap with the first separationmold pattern 17 ps and the second spacers 33 p covering both sidewallsof the first separation mold pattern 17 ps when viewed in plan view.

The second mold patterns 17 p and the first separation mold pattern 17ps may be selectively removed. The intermediate mold layer 17 of theperipheral circuit region PR may be removed during this processing stepto expose the first etch stop pattern 8 p of the peripheral circuitregion PR.

The maximum width W5 of each of the second spacers 33 p may besubstantially equal to the maximum width W2 of the first spacer 31 p(W5=1F). A width W6 of each of the second etch stop patterns 18 p may beabout three times the maximum width W2 of the first spacer 31 p (W6=3F).A distance L3 between adjacent ones of the second etch stop patterns 18p may be substantially equal to the maximum width W2 of the first spacer31 p (L3=1F).

A pair of the second spacers 33 p may be disposed on each separationetch stop pattern 18 ps. Outer walls of each pair of second spacers 33 pmay be coplanar with the outer sidewalls of the underlying separationetch stop pattern 18 ps. A distance between the pair of spacers 33 pthat are on the separation etch stop pattern 18 ps may be greater thanthe maximum width W2 of the first spacer 31 p as a width W7 of theseparation etch stop pattern 18 ps may be greater than about three timesthe maximum width W2 of the first spacer 31 p (W7>3F).

In the method for fabricating the semiconductor device according to thepresent embodiment, the third photoresist pattern PP3 overlapping withthe portion of the separation region SA is further formed unlike FIGS.23A and 23B, so the separation etch stop pattern 18 ps having the widthW7 that is greater than the width W6 of the second etch stop pattern 18p may be formed.

Referring to FIGS. 28A and 28B, the lower mold layer 7 may be etchedusing the second spacers 33 p, the second etch stop patterns 18 p, andthe separation etch stop pattern 18 ps as etch masks to form third moldpatterns 7 p. The third mold patterns 7 p may be formed on theperipheral circuit region PR as well as the cell array region CR. Thethird mold patterns 7 p may include a second separation mold pattern 7ps. A shape of the second separation mold pattern 7 ps may correspond tothat of the separation etch stop pattern 18 ps when viewed in plan view.

In more detail, a width W8 of the third mold pattern 7 p correspondingto the second etch stop pattern 18 p may be about three times themaximum width W2 of the first spacer 31 p (W8=3F). A width W9 of thesecond separation mold pattern 7 ps corresponding to the separation etchstop pattern 18 ps may be greater than about three times the maximumwidth W2 of the first spacer 31 p (W9>3F). For example, the width W8 ofthe third mold pattern 7 p on the separation region SA may be equal toabout three times the maximum width W2 of the first spacer 31 p (W6=3F),and the width W9 of the second separation mold pattern 7 ps on theseparation region SA may be equal to nine times the maximum width W2 ofthe first spacer 31 p (W9=9F). A distance L4 between adjacent ones ofthe third mold patterns 7 p that correspond to the second etch stoppatterns 18 p may be substantially equal to the maximum width W2 of thefirst spacer 31 p (L4=1F).

Referring to FIGS. 29A and 29B, the etch stop layer 5 may be etchedusing the third mold patterns 7 p as etch masks to form insulatingpatterns 5 p. Shapes of the insulating patterns 5 p may correspond tothose of the third mold patterns 7 p when viewed in plan view.

The insulating patterns 5 p may include first separation insulatingpatterns 5 psa and a second separation insulating pattern 5 psb that arein the separation region SA. Shapes of the first separation insulatingpatterns 5 psa may correspond to the third mold patterns 7 p on theseparation region SA when viewed in plan view. A shape of the secondseparation insulating pattern 5 psb may correspond to that of the secondseparation mold pattern 7 ps when viewed in plan view.

Conductive lines 51 and 55 may be formed to fill spaces between theinsulating patterns 5 p. The conductive lines 51 and 55 may include cellinterconnections 51 and peripheral interconnections 55. The peripheralinterconnections 55 may fill the spaces between the insulating patterns5 p disposed on the peripheral circuit region PR.

The cell interconnections 51 adjacent the first separation insulatingpatterns 5 psa may be spaced apart from each other by the firstseparation insulating patterns 5 psa. The cell interconnections 51adjacent the second separation insulating pattern 5 psb may be spacedapart from each other by the second separation insulating pattern 5 psb.In more detail, the cell interconnections 51 on the cell array region CRmay include first, second and third cell interconnections 51 a, 51 b, 51c that extend in parallel to each other in a first direction D1. Thefirst separation insulating pattern 5 psa may be disposed between thefirst and second cell interconnections 51 a, 51 b.

A width W11 of each of the cell interconnections 51 may be substantiallyequal to the maximum width W2 of the first spacer 31 p (W11=1F). Adistance L5 between adjacent ones of the cell interconnections 51 may besubstantially equal to the maximum width W2 of the first spacer 31 p(L5=1F). However, a distance L6 between adjacent ones of the cellinterconnections 51 that have the first separation insulating pattern 5psa interposed therebetween may be about three times the maximum widthW2 of the first spacer 31 p (L6=3F). In addition, a distance L7 betweenadjacent ones of the cell interconnections 51 that have the secondseparation insulating pattern 5 psb interposed therebetween may begreater than about three times the maximum width W2 of the first spacer31 p (L7>3F).

In the method for fabricating the semiconductor device according to thepresent embodiment, conductive lines 51 and 55 having a fine pitch thatis smaller than the minimum pitch realized by an exposure process may beformed using three photolithography processes and two spacer formationprocesses. In addition, the third photoresist pattern PP3 overlappingwith the portion of the separation region SA may formed in a thirdphotolithography process unlike the embodiment of FIGS. 13A to 22A and13B to 22B, so a node separation region may be further defined. As aresult, it is possible to increase the width of one or some of theseparation insulating patterns (e.g., the width of the second separationinsulating pattern 5 psb).

As shown in FIGS. 29A and 29B, in the semiconductor device according tothe present embodiment, the insulating patterns 5 p may include firstseparation insulating patterns 5 psa and a second separation insulatingpattern 5 psb which are disposed on the cell array region CR. Cellinterconnections 51 may be spaced apart from each other with each of thefirst and second separation insulating patterns 5 psa and 5 psbinterposed therebetween.

A distance L6 between adjacent ones of the cell interconnections 51 thathave the first separation insulating pattern 5 psa interposedtherebetween may be about three times the maximum width W2 of the firstspacer 31 p (L6=3F). For example, a distance between first and secondcell interconnections 51 a, 51 b may be about 3F. A distance L7 betweenadjacent ones of the cell interconnections 51 that have the secondseparation insulating pattern 5 psb interposed therebetween may begreater than about three times a width W11 of the cell interconnection51 (L7>3F).

Descriptions to other elements of the semiconductor device according tothe present embodiment may be similar to those to corresponding elementsof the semiconductor device described with reference to FIGS. 22A and22B.

FIG. 30 is a schematic block diagram illustrating an embodiment of anelectronic system including a semiconductor device according toembodiments of the inventive concepts.

Referring to FIG. 30, an electronic system 1100 may be applied to apersonal digital assistant (PDA), a portable computer, a web tablet, awireless phone, a mobile phone, a digital music player, a memory card,or other electronic products receiving and/or transmitting informationdata by wireless.

The electronic system 1100 may include a controller 1110, aninput/output (I/O) unit 1120, a memory device 1130, an interface unit1140, and a data bus 1150. At least two of the controller 1110, the I/Ounit 1120, the memory device 1130, and the interface unit 1140 maycommunicate with each other through the data bus 1150.

The controller 1110 may include at least one of a microprocessor, adigital signal processor, a microcontroller, or other logic deviceshaving a similar function to any one thereof. The memory device 1130 maystore data and/or commands executed by the controller 1110. The I/O unit1120 may receive data or signals from the outside of the system 1100 ormay transmit data or signals to the outside of the system 1100. Forexample, the I/O unit 1120 may include a keypad, a keyboard, and/or adisplay device.

The memory device 1130 may include at least one of the semiconductordevices according to the above mentioned embodiments of the inventiveconcepts. In addition, the memory device 1130 may further include atleast one other memory device.

The interface unit 1140 may transmit electrical data to a communicationnetwork and/or may receive electrical data from a communication network.

FIG. 31 is a schematic block diagram illustrating an embodiment of amemory card including a semiconductor device according to embodiments ofthe inventive concepts.

Referring to FIG. 31, a memory card 1200 used for storing massive datamay include a flash memory device 1210 implemented with at least one ofthe semiconductor devices according to the aforementioned embodiments ofthe inventive concepts. The memory card 1200 may include a memorycontroller 1220 that controls data communication between a host and theflash memory device 1210.

A static random access memory (SRAM) device 1221 may be used as aworking memory of a central processing unit (CPU) 1222. A host interface(I/F) unit 1223 may be configured to include a data communicationprotocol between the memory card 1200 and the host. An error check andcorrection (ECC) block 1224 may detect and correct errors of data whichare read out from the memory device 1210. A memory interface unit 1225may interface with the flash memory device 1210. The CPU 1222 maycontrol overall operations for data communication of the memorycontroller 1220. Even though not shown in the drawings, the memory card1200 may further include a read only memory (ROM) device that storescode data used for interfacing with the host.

The flash memory device according to the above mentioned embodiments maybe provided into a memory system such as a solid state disk (SSD).

FIG. 32 is a schematic block diagram illustrating an embodiment of aninformation processing system including a semiconductor device accordingto embodiments of the inventive concepts.

Referring to FIG. 32, a flash memory system 1310 according to theinventive concepts may be installed in an information processing system1300 such as a mobile device or a desk top computer. The informationprocessing system 1300 according to the inventive concepts may include amodem 1320, a central processing unit (CPU) 1330, a random access memory(RAM) 1340, and a user interface unit 1350 which are electricallyconnected to the flash memory system 1310 through a system bus 1360. Theflash memory system 1310 may have the substantially same structure asthe memory card 1200 described above. In other words, the flash memorysystem 1310 may include a flash memory device 1311 and a memorycontroller 1312. The flash memory system 1310 may store data processedby the CPU 1330 or data inputted from an external system. In someembodiments, the flash memory system 1310 may be realized as a solidstate disk (SSD). In this case, the information processing system 1300may stably store large amounts of data in the flash memory system 1310.In addition, as reliability of the flash memory system 1310 increases,the flash memory system 1310 may reduce processing resources that areconsumed in performing error correction operations. Thus, theinformation processing system 1300 may perform a fast data communicationfunction. Even though not shown in the drawings, the informationprocessing system 1300 may further include, for example, an applicationchipset, a camera image processor (CIS), and/or an input/output (I/O)unit.

The semiconductor devices and/or the memory system described above maybe encapsulated using various packaging techniques. For example, thesemiconductor devices and/or the memory system according to theaforementioned embodiments may be encapsulated using any one of apackage on package (POP) technique, a ball grid arrays (BGAs) technique,a chip scale packages (CSPs) technique, a plastic leaded chip carrier(PLCC) technique, a plastic dual in-line package (PDIP) technique, a diein waffle pack technique, a die in wafer form technique, a chip on board(COB) technique, a ceramic dual in-line package (CERDIP) technique, aplastic metric quad flat package (PMQFP) technique, a plastic quad flatpackage (PQFP) technique, a small outline package (SOP) technique, ashrink small outline package (SSOP) technique, a thin small outlinepackage (TSOP) technique, a thin quad flat package (TQFP) technique, asystem in package (SIP) technique, a multi-chip package (MCP) technique,a wafer-level fabricated package (WFP) technique and a wafer-levelprocessed stack package (WSP) technique.

In the methods for fabricating the semiconductor device according to theinventive concepts, conductive lines having a fine pitch that is smallerthan the minimum pitch that can be realized by the exposure process maybe formed using two or three photolithography processes and two spacerformation processes. In addition, it is possible to improve thealignment margin of the node separation region of the conductive lines.

While the inventive concepts have been described with reference toexample embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirits and scopes of the inventive concepts. Therefore, itshould be understood that the above embodiments are not limiting, butillustrative. Thus, the scopes of the inventive concepts are to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing description.

What is claimed is:
 1. A method for fabricating a semiconductor device,the method comprising: sequentially forming an etch target layer and alower mold layer on a substrate, the substrate including a cell arrayregion and a peripheral circuit region and the etch target layerincluding a separation region; forming a first etch stop pattern on thelower mold layer, the first etch stop pattern vertically overlapping theseparation region; forming an intermediate mold layer on the lower moldlayer, the intermediate old layer at least partially covering the firstetch stop pattern; forming first mold patterns on the intermediate moldlayer; forming first spacers on sidewalls of the first mold patterns;etching the intermediate mold layer using the first spacers as etchmasks to form second mold patterns, where portions of the second moldpatterns are on the first etch stop pattern; forming second spacers onsidewalls of the second mold patterns; etching portions of the firstetch stop pattern to form second etch stop patterns during the formationof the second spacers; etching the lower mold layer using the secondspacers and the second etch stop patterns as etch masks to form thirdmold patterns; etching the etch target layer using the third moldpatterns as etch masks, to form insulating patterns; and formingconductive lines in spaces between the insulating patterns.
 2. Themethod of claim 1, wherein a pair of the second spacers are disposed onrespective ones of the second etch stop patterns, wherein outersidewalls of each pair of second spacers are coplanar with outersidewalls of the respective ones of the second etch stop patterns, andwherein a distance between adjacent ones of the pairs of second spacersis substantially equal to a maximum width of the second spacer.
 3. Themethod of claim 1, wherein forming the first etch stop patterncomprises: sequentially forming an etch stop layer and a preliminarymold layer on the lower mold layer; forming a first photoresist patternon the preliminary mold layer; etching the preliminary mold layer usingthe first photoresist pattern as an etch mask to form a fourth moldpattern; and etching the etch stop layer using the fourth mold patternas an etch mask to form the first etch stop pattern, wherein the firstphotoresist pattern vertically overlaps the separation region.
 4. Themethod of claim 1, wherein the separation region is on the cell arrayregion.
 5. The method of claim 4, wherein the first etch stop patternincludes a plurality of first etch stop patterns, and wherein one of thefirst etch stop patterns that is on the peripheral circuit regionexposes a portion of the lower mold layer that is on the peripheralcircuit region.
 6. The method of claim 5, wherein the first and secondmold patterns are formed on the cell array region, and wherein the oneof the first etch stop patterns that is on the peripheral circuit regionremains when the second etch stop patterns are formed on the cell arrayregion.
 7. The method of claim 4, wherein forming the first moldpatterns comprises: forming an upper mold layer on the intermediate moldlayer; forming second photoresist patterns on the upper mold layer, thesecond photoresist patterns covering the portions of the upper moldlayer that are on the peripheral circuit region but exposing portions ofthe upper mold layer of the cell array region; and etching the uppermold layer using the second photoresist patterns as etch masks to formthe first mold patterns on the cell array region.
 8. The method of claim4, wherein forming the first spacers comprises: forming a first spacerlayer covering the first mold patterns; forming a third photoresistpattern covering the portions of the first spacer layer that are on theperipheral circuit region, the third photoresist pattern exposing atleast a portion of the first spacer layer on the cell array region; andanisotropically etching the first spacer layer using the thirdphotoresist pattern as an etch mask to form the first spacers.
 9. Themethod of claim 1, further comprising: forming a first mask layer on theintermediate, mold layer before forming the first mold patterns; andetching the first mask layer using the first spacers as etch masks toform first mask patterns, wherein the first mask patterns are also usedas etch masks when the intermediate mold layer is etched, and whereinthe first mask patterns remain on the second mold patterns after theformation of the second mold patterns.
 10. The method of claim 9,wherein forming the second spacers and the second etch stop patternscomprises: forming a second spacer layer on the second mold patterns andthe first mask patterns; anisotropically etching the second spacer layeruntil the first mask patterns are exposed, thereby forming the secondspacers; and anisotropically etching portions of the first etch stoppattern that are exposed by the first mask patterns, the second spacersand the second mold patterns to form the second etch stop patterns. 11.The method of claim 1, wherein a width of at least one of the first moldpatterns is about three times a maximum width of one of the firstspacers.
 12. The method of claim 1, wherein a distance between adjacentones of the first mold patterns is about five times a maximum width ofone of the first spacers.